In any given geographical area, there may be multiple wireless communications networks that can be used to determine the position location of a User Equipment (UE), if the networks are synchronized with respect to time. Achieving synchronization within a network or between different networks, however, may require a significant engineering burden. As the primary purpose of networks such as cellular, Wi-Fi, and broadcast networks is not to provide position location determinations, intra-system or inter-system synchronization is typically not done or is loosely done. For example, Wi-Fi or broadcast networks typically are not synchronized with respect to time. Moreover, some broadcast networks, such as single frequency networks (SFNs), may be loosely synchronized. Also, many cellular networks, such as some Long Term Evolution (LTE) networks, are loosely synchronized. As used herein, the term “loosely synchronized” means imprecisely (or partially) synchronized such that timing errors between different transmitters would result in imprecise position location determinations as compared to the precision of position location determinations that could be achieved if timing errors between different transmitters in the network were reduced.
Networks that are not synchronized with respect to time cannot be used for position location based on the time of signal arrival at a UE. Moreover, networks that are loosely synchronized, such as some LTE networks, may introduce significant errors in the determination of position location of the UE because of timing errors caused by imprecise synchronization between different transmitters in the networks.